Morphine Milligram Equivalent Conversion for Oxycodone
The conversion factor for oxycodone to morphine milligram equivalents (MME) is 1.5, meaning each milligram of oxycodone equals 1.5 MME. 1
How to Calculate MME from Oxycodone
To convert any oxycodone dose to MME, multiply the total daily oxycodone dose by 1.5. 1
Practical examples:
- Oxycodone 10 mg twice daily = 20 mg total daily dose × 1.5 = 30 MME/day 1
- Oxycodone 5 mg four times daily = 20 mg total daily dose × 1.5 = 30 MME/day 1
- Oxycodone 40 mg daily × 1.5 = 60 MME/day 2
Critical Safety Warnings When Using This Conversion
These conversion factors are estimates only and cannot account for individual variability in genetics and pharmacokinetics. 1
Never use the calculated MME dose to determine doses when converting FROM one opioid TO another opioid. 1 When rotating between opioids, the new opioid should be dosed at 25-50% lower than the calculated equianalgesic dose to avoid accidental overdose due to incomplete cross-tolerance. 3, 2, 4
Clinical Context for MME Calculations
The CDC established these conversion factors primarily for:
- Calculating total daily opioid burden for risk assessment 1
- Monitoring cumulative opioid exposure across multiple prescriptions 1
- Identifying patients at higher risk for overdose (particularly at ≥50 MME/day and ≥90 MME/day thresholds) 1
Doses ≥50 MME/day warrant careful reassessment of individual benefits and risks before any further dosage increases. 1
Doses ≥90 MME/day are associated with progressively increased overdose risk. 3
Common Pitfall to Avoid
The most dangerous error is using MME calculations bidirectionally—the 1.5 conversion factor tells you how much morphine equivalence you're prescribing, but it should never be used in reverse to calculate a new opioid dose when switching medications. 1 Always reduce by 25-50% when rotating opioids due to incomplete cross-tolerance. 3, 2, 4